{"id":"CVE-2026-33939","sourceIdentifier":"security-advisories@github.com","published":"2026-03-27T22:16:20.857","lastModified":"2026-09-04T13:19:26.173","vulnStatus":"Modified","cveTags":[],"descriptions":[{"lang":"en","value":"Handlebars provides the power necessary to let users build semantic templates. In versions 4.0.0 through 4.7.8, when a Handlebars template contains decorator syntax referencing an unregistered decorator (e.g. `{{*n}}`), the compiled template calls `lookupProperty(decorators, \"n\")`, which returns `undefined`. The runtime then immediately invokes the result as a function, causing an unhandled `TypeError: ... is not a function` that crashes the Node.js process. Any application that compiles user-supplied templates without wrapping the call in a `try/catch` is vulnerable to a single-request Denial of Service. Version 4.7.9 fixes the issue. Some workarounds are available. Wrap compilation and rendering in `try/catch`. Validate template input before passing it to `compile()`; reject templates containing  decorator syntax (`{{*...}}`) if decorators are not used in your application. Use the pre-compilation workflow; compile templates at build time and serve only pre-compiled  templates; do not call `compile()` at request time."}],"affected":[{"source":"security-advisories@github.com","affectedData":[{"vendor":"handlebars-lang","product":"handlebars.js","versions":[{"version":">= 4.0.0, < 4.7.9","status":"affected"}]}]},{"source":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c","affectedData":[{"vendor":"Red Hat","product":"Cluster Observability Operator 1.5.0","defaultStatus":"affected","collectionURL":"https://catalog.redhat.com/software/containers/","packageName":"cluster-observability-operator/logging-console-plugin-pf4-rhel9","cpes":["cpe:/a:redhat:cluster_observability_operator:1.5::el9"],"versions":[{"version":"1782839279","lessThan":"*","versionType":"rpm","status":"unaffected"}]},{"vendor":"Red Hat","product":"Cluster Observability Operator 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